Comment 4 for bug 1016165

Situation is still present in the 4.1.18 version of VirtualBox and the latest version of the kernel.
$ uname -r
3.5.0-2-generic

Error reported when installing the guest additions:
Building the VirtualBox Guest Additions kernel modules
The headers for the current running kernel were not found. If the following
module compilation fails then this could be the reason.

Building the main Guest Additions module ...fail!
(Look at /var/log/vboxadd-install.log to find out what went wrong)
Doing non-kernel setup of the Guest Additions ...done.
Installing the Window System drivers
Installing X.Org Server 1.11 modules ...done.
Setting up the Window System to use the Guest Additions ...done.
You may need to restart the hal service and the Window System (or just restart
the guest system) to enable the Guest Additions.

Installing graphics libraries and desktop services components ...done.

Attached /var/log/vboxadd-install.log which still indicates:
/tmp/vbox.0/r0drv/linux/memobj-r0drv-linux.c:1150:9: error: implicit declaration of function ‘do_mmap’ [-Werror=implicit-function-declaration]